Visual Impairment Causes

Low vision is the term used to describe reduced eyesight – either blurred vision (usually 20/70 or worse) or an incomplete field of view – that cannot be fully corrected with eyeglasses, contact lenses or eye surgery. This loss of vision that makes it hard or impossible to carry out daily tasks without specialised adaptations. Vision impairment can affect visual acuity, where the eye does not see objects as clearly as usual. It may also affect loss of visual field, where the eye cannot see as wide an area as usual without moving the eyes or turning the head. Some people are also born with low vision.

There are varying levels of visual impairment. The eyesight of a person with low vision may be hazy from cataracts, blurred or partially obscured in the central visual zone because of macular degeneration or distorted or blurred from diabetic retinopathy. The primary causes of low vision are eye diseases, such as macular degeneration, glaucoma and diabetic retinopathy. But low vision can also be inherited or caused by an eye or brain injury. A person with low vision is not blind as they have some useful sight but the degree of their visual impairment can make daily tasks, such as reading and driving, difficult or impossible.Though children as well as adults can be visually impaired, low vision is mostly a problem that afflicts the elderly

Finding a way to read comfortably is one of the most difficult challenges for visually impaired people. Ash Technologies offers a wide range of magnification aids for low vision - from portable magnifiers such as Quicklook to a desktop CCTV’s like Eclipse or Presto.

 

The leading causes of vision impairment and blindness include:

1. Age-related Macular Degeneration

What is age-related macular degeneration (AMD)?

ASH  MacularAMD is a progressive condition that affects the macula. The macula, located at the back of the eye is a small spot on the retina which is responsible for central vision. As a result, people with amd experience a loss of sight to their central vision and rely on their peripheral vision to see. There are two types of amd; the “dry” form and the “wet” form. The dry form is far more common and accounts for 85% - 90% of all cases. It is the milder version of the two and has a significantly lower vision loss than the wet form. In both cases, however, amd is highly unlikely to lead to total blindness as the peripheral vision is never affected. It is the most common cause of low vision in people over 60 years of age.

What are the symptoms?
 
The loss of central vision can occur gradually or quite quickly. There is heightened sensitivity to light and objects and shapes become blurred. Finding it harder to adjust to varying levels of light and an increased discomfort to glare makes it difficult to see objects in ones path.
 

2. Glaucoma

ASH  GlaucomaGlaucoma is a group of eye diseases that affects the optic nerve of the eye; the nerve that sends information from the eye to the brain. There are two main forms: open angle and closed angle. Open angled affects 95% of all diagnosed cases of glaucoma. Both forms result in the loss of peripheral vision. Elevated pressure in the eye can lead to glaucoma although not exclusively.

What are the symptoms?

Different forms of glaucoma have different symptoms. However, the most common form, open-angle, has no symptoms initially. Gradually, peripheral vision loss will occur and if not treated properly will result in blindness. Other symptoms include a difficulty in adjusting to darkness and focusing on items up close.
 
 
 

3. Cataract 

ASH  CataractsThe natural lens of the eye is responsible for focusing light and making images clear and sharp. A cataract is a clouding of this natural lens. This means vision becomes cloudy and both central and peripheral vision becomes blurred. The main cause of cataracts is ageing and it is the leading cause of vision loss among the over 55 age bracket. Diseases such as diabetes, eye injuries and different types of medications may also cause cataracts.

What are the symptoms?

Symptoms of cataracts include double or blurred vision. There may also be a diminishing ability to distinguish colour and a heightened sensitivity to light and glare.


 
 

4. Diabetic Retinopathy

ASH  Diabetic RetinopathyDiabetic Retinopathy is a result of diabetes and affects the retina part of the eye. The retina often referred to as the “seeing part of the eye” is a light sensitive tissue that is located at the back of the eye. Diabetetic retinopathy causes the blood vessels of the eyes to become blocked and can result in vision loss and blindness.

What are the symptoms?

In the early stages, there are no symptoms and changes in vision may not occur until it is in an advanced stage. It is important that once diagnosed with diabetes to take an eye test once every two years. It is during an examination that characteristic changes of the retina can be found.
 

 

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